Jean L. Turner

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Hidden from optical view in the starburst region of the dwarf galaxy NGC 5253 lies an intense radio source with an unusual spectrum which could be interpreted variously as nebular gas ionized by a young stellar cluster or nonthermal emission from a radio supernova or an AGN. We have obtained 11.7 and 18.7 µm images of this region at the Keck Telescope and(More)
We have imaged emission from the millimeter lines of eight molecules—C 2 H, C and SO—in the central half-kiloparsec of the nearby spiral galaxy IC 342. The 5 00 ($50 pc) resolution images were made with the Owens Valley Millimeter Array. Using these and previously published CO and HCN images, we obtain a picture of the chemistry within the nuclear region on(More)
This paper presents a new coherent optical method whereby the partial derivatives of the contour of an object are measured. The object to be studied is immersed in a refractive medium and is imaged by a camera with a shearing device. The processed photographic plate which has been doubly exposed in the image plane with the refractive medium changed between(More)
Little is known about the origins of globular clusters, which contain hundreds of thousands of stars in a volume only a few light years across. Radiation pressure and winds from luminous young stars should disperse the star-forming gas and disrupt the formation of the cluster. Globular clusters in our Galaxy cannot provide answers; they are billions of(More)
Evaluation of the surface morphology of short-term retrieved cross-linked acetabular components requires differentiation between the features generated during machining and the smaller-scale morphologies generated during the in vivo wear process. Previously, the distinction between the waviness of machining and the roughness of wear has been related to the(More)
23 (ref. 26). 30 Dor is 200 times larger and 100–1,000 times less dense than the supernebula in NGC5253, and its exciting star cluster R136 is 10–100 times less massive than the cluster in NGC5253 (ref. 27). The escape velocity for 30 Dor is less than the thermal sound speed of 10 km s 21 so its gas motions are determined by winds and turbulence rather than(More)
A method for determining the complete surface strain field on rubber structures is described. The technique consists of photographically depositing a set of grid lines on the surface of a photoelastic birefringent coating. The coating is bonded to the surface of the object of interest. Photoelastic data together with grid photographs provide sufficient(More)
We present ∼ 3 resolution maps of CO, its isotopologues, and HCN from in the center of Maffei 2. The J=1–0 rotational lines of 12 CO, 13 CO, C 18 O and HCN, and the J=2–1 lines of 13 CO and C 18 O were observed with the OVRO and BIMA arrays. The lower opacity CO isotopologues give more reliable constraints on H 2 column densities and physical conditions(More)
Gas clouds in present-day galaxies are inefficient at forming stars. Low star-formation efficiency is a critical parameter in galaxy evolution: it is why stars are still forming nearly 14 billion years after the Big Bang and why star clusters generally do not survive their births, instead dispersing to form galactic disks or bulges. Yet the existence of(More)